Crane propelling system and control thereof



July 22, 1952 yw. s. BURDICK ET An.

CRANE PROPELLING SYSTEM AND CONTROL' THEREOF v Filed June 21, 1945 2SHEETS-SHEET 1 uffi. ana/:1114524415115 July 22, 1952 v w. s. BURDICK ETAl.

` l CRANE PBOPELLING SYSTEM AND CONTROL THEREOF Filed June 21, 1945 2SHEETS- SHEET 2 Patented July 22, 1952 TENT orrlfcizs'''7 CRANEvPROPELLING SYSTEM vAN D CONTROL THEREOF Will S. Burdick, Wauwatosa,Henry S. Jacobs,V

Milwaukee, and Karl Schneider, Greendale, Wis., assignors toHarnischfegcr Corporation, Milwaukee, Wis., a corporation of WisconsinApplication June 21, 1945, Serial No. 600,812

1. This invention relates to propelling systems and controls thereforfor travelingbase power excavators, cranes and the like, hereinaftercalled cranes', being of particular usefulness in machines of thischaracter in which a so-called full revolving cab is employed. Theinvention resides in an'apparatus of this type in which a permanentdriving connection between one oi the two base treads and a propellingpower source is maintained at all times, the other tread being arrangedto be alternatively locked to form a pivot for steering or connectedtosaid propelling power source for traveling motion, andl in which anindependent brake operable to arrest motion of said propelling powerSource is provided. Moreover, the invention sometimes resides inapparatus of this characterin combination with certain controls in whichthe propelling power source includes a reversible motor mounted on therevolving cab and permanently joined by transmission gearing with atleast one of the treads.

The common form of self-propelled traveling crane comprises a propelling'base formed of a carbody mounted on a pair ofendless treads disposedone on 'each side of the carbody. Mounted on the carbodyl and arrangedfor revolving motion is a deck and a cab from which the lifting boom orother Workl instrumentality extends. Carried on the cab .deck are thenecessary mechanisms by which the work functions of the machine areproduced. Usually the motor' or other prime mover, which is relied uponto produce the traveling motion of the base treads, is mounted on thedeck and arranged to be connected through transmission gearing extendinginto the carbodyand thence to, the treads. AI-Ieretofore in all suchsystems, provision has been made for disconnecting such transmissiongearing when revolving motionot the' cab is desired. When thevtransmission is thus disconnected! control yof the propelling of theapparatusA is Vlost and this -loss of control gives rise to, Certainhazards. Through the apparatus of this invention continuous control ismaintained .at all times and the hazards heretofore prevailing have beeneliminated. v

This invention is herein described by reference to the accompanyingdrawings which form a part hereof and in'which there isset forth byvWayy of illustration andvnot oi limitation one form-in which theapparatus of this invention may be embodied. Y. In the. drawnssz' 'YFig. luis a side view in elevation with parts broken awayl and invsection offoneform offthe apparatus i this invention; and

4 Claims. (c1. 18o- 6.58)

Fig. 2 is a fragmentary top planview in section viewed throughthe plane2-2 indicated in Fig. 1 joined with a` diagrammaticfshowing of thecontrol system used in connection therewith.

As shown inFig. 1 the apparatus of this inven tion is embodied in arevolving cab crane having supporting treads l and 2,."shown in'outline'only which are mounted upon andSe'rVe asthe support for a'carbody 3.librtendingv upwardly from the carbody 3 is a pedestaljl bearingl anupwardly facing roller ring 5 surrounded by a swing'gear S. Supporteduponthe roller ring 5 is afrace composed of a. pluralityoi rollersfl,-which turn form the support for an' upper roller ringe'v which bears theweight of the decl; r9 oi the revolvable cab l0.- I, 1 f, f Centrally,disposed with Vrespect to the roller ring 5 and extending vertiallyiromthe pedestal 4 is a center gudgeonsupporting sleeve'l lfl" which carriesand rigidly ,supports a .hollow fgudgeon pin IL The cab I0 and itsdsck.Sfafeihllssur ported' and guided for fullrevolving l Inoveinent onthe carbody 3 and a boom i3 or other'wo'rlzl instrumentality .supportedOrl thel deckt caribe swung to any position desired.: In orderto'produce"` swinging movemlilt' a' [swing-"motor""lt mountedwontheldeck @fis connectedthrough transmission gearing ,not lshowin with''swing pinon 7,-" Treadsl Ig'and '2 are made up of a pluralityoiinterconnected 'shoe elements arranged to be en'-` gaged and drivendouble' propelling sprockets lef-'i5 and l1-ll,frespectively; vSprocketsI G-TIG aremounted for rotation with and uponjst'ulo.

shaft 'l it which is rotatablymounted in bearings l l 3 andY i lo 'inthe carbody 3'. Also mounted upon sh'aftjl for rotation therewith isanal vreduction gear i9 which is `disposed in drvenmesh'ingrelationship'wfith a final reduction pinion-120. Pinionl 2 0 is mounteduponand'vkeyed to'af's'ubaxle shaft :2l 'carried "in bearings 22 and 23.Keyedjtothe opposite endoff'shaft 2| is a'bevel gearA Z'fwhich' in turnis r`in meshingv 'engagement with laloevel pinion 25fsec'ure`d to theend ofa forwardly l'extending propellershaft26.

Sprockets l-1'l'l are Lsiinilar in forfrn` to sprockets lB-l6fand aremounted upon a stub shaft '2 l` for 'rotationtherewithf the `latterybeing carried irl-bearing :s and lze provided-therefor inI the` carbody'3; iinal reduction" gear-3D i sel cured to and'fnounted upon the' shaft2l, i pose'dfinlmesning engagement wit'hfa final? r 'uc-Y ti'on pin-ion3l.- The' lfinal reduction pinion' A3| is secured tothe endo'f asubaxleshaft 32fca`rriediii'lbearings 33farrd 342 inthe carbody3'.' "The treadsI and 2 are driven in unison, thus per-r mitting straight, forward orreverse movement of the apparatus depending upon the 'direction ofrotation of shaft 26.

'Ihe opposite side of internal dog clutch member 36 is provided with atoothed rim 39 disposed so as to meshingly engage an external dog brakemember 40 integrally yformed as a part of the carbody -3 when member, 36is shifted from the position in whichit is shown in Fig. 2 to theopposite position. VWhenthe member 36 is in engagementwithl the dogbrake40, shaft 33 and, as a consequence, tread 2 is positively held againstmotion-whiletread'lis free to be movedeither forwardly orbackwardly byrotation of shaft 26. In this way steeringof-the Vapparatus ispermitted,-since either a right hand or a left hand turn may bemade atwill depending upon the direction of rotation of-shaft 2,6. VInexecuting such a 1 steering movement the tread. 2, being stationary,

acts, as it were, asa pivot around which tread I maytravel. Y l

Shaft 26 is mounted for rotation in bearings 4I and 42 provided thereforin carbody 3, and carries rigidlyfsecured thereto at its opposite end abevelgear43l The gear V43 in turn is in meshing engagement withabevelpinion 44 secured to the end of .a drop shaft45 journalled inbearings 46 and 41 mounted within the hollow gudgeon pin I2.- The upperend of drop shaft 45 extends above the top of-deck-S to a rigidengagement with a main propelling gear 48 mountedin a housing 4 9.v-Also contained within the housing 49v in driving relationship 4withgear 48 is a constantly meshed train ofrv reduction gearing composed ofpinion 50, gear 5I, pinion 52 and gear 53.- Gear -53 is in turn inmeshing engagement at all `times with pinion 54 secured to the shaft ofa-reversiblepropelling motor 55.

'It may be observed vthat the complete transmission train from motor 55to tread I is permanently engaged so that motor 55 may be operatedat'any time Ato control the movement of this tread .and if themember 36be in the position shown in Fig. 2, to control-the movement of bothtreads in unison. Any tendency Vof the'apparatus to run away, or, turnor crab on a slope (which are hazards to be avoided) can be immediatelychecked or Fcontrolled by the-operator through control of motorV 55alone, although additional control to be hereinafter described is alsoprovided toincrease the safety of the apparatus.

The permanent engagement ofV the complete transmission Vtrain oftheapparatus of this invention is maintained in spite of the revolvabilityofthe c ab AI 0 and this is rendered possible bythe employment of afreely revolvable motor 55.4 That is'to say; theymoto r 55 is notprovided with the -usualggbrakegwhich arrests the `shaft when noelectric jpowerj is being admitted. ',When thecab I0 is caused torevolve ,through Vthe action of roll about the periphery of gear 48. Inspite of 4 the very substantial driving ratio between pinion 50 andpinion 54 the shaft of motor 55 even at maximum rates of swing of cab I0is substantially less than the normal operating speed of motor .55,since the swingingmotion of cab I6 is a very deliberate motion, and theratio of reduction between the swing gear 6 and the swing motor I4 issubstantially greater than the ratio of reduction between pinion 54 andgear 48. By thus relating the ratios of reduction, as above explained,permanent and positive connection between the motor 55 and at least oneof the treads may be maintained without damage to the motor 55 andwithout any tendency on the part of treads I and 2 to creep duringswinging movement of the c ab I0. It is even feasible to carry on bothswinging and traveling movements simultaneously.

As appears more clearly in Fig. 1 a brake drum 56 is secured to theshaft 26 and is surrounded by a brake band 51. As shown in Fig. 2the-band 51 'is normally applied by leased by a hydraulic'cylinder 58.For the pur-l pose of furnishing fluidfor the actuation of-cyl-` inder'58 a positive 'displacement pump of any suitable form, forexample, agear pump, is provided at 60 and connected through piping-6I and 62 withthe cylinder 59. VThe pump'fis arranged to draw fluid through an inletpipe 83 which joins with a iiuid reservoir or sump 64. In order tooperate the pump 60 an -electric motor 65 of special design ispreferably employed.

The motor 65 is a three phase squirrel cage type of motor, the statorofwhich is wound to have an exceptionally high impedance, such that themotor 65 may remain stalled with electric power applied to it forindefinite periods without destructive overheating. Such a motor willcontinue to rotate-until resisting torque exceeds 'a' predeterminedvalue whereupon the motor-ceases to turn-while continuing .to applytorque against the resistance .equal to' said predetermined maximumtorque... A.motor of this type will hereinafter be referred toforconvenience as al torque motor.

The motor V65`fis,mounted inl any convenient location desired uponthecarbody `3 and is connected by leads 66, 61 and 68 with correspondingslip rings 69,.'10 and 1I which are rigidly mounted upon and surroundthe gudgeon pin I2 as appears more clearly in Fig. 1. Correspondingbrushes 12; 13 and 14 mounted onthe underside. ofthe deck 8, but-showndiagrammatically only in Fig. 2, slidingly engage the slip .rings'69,1I] and 1I and provide a means by which-electrical Yaccess to the motor65 'mayY Abe. obtained from within the cab IIJ.- Mounted within the cabI0 at the operators vcontrol station, not shown, is a drum typecontroller 15 whichv is joined with the brushes 12, 13 and 14 by leads.16, -11and 18. Commutator segments 19, v8l] and-8| of the controller'I5 upon movement toward closed position electrically join leads 16,711and 18 through leads 82,83 and Y84 with power-mains .85,8 6 and 81.'v j

Upon the closing of the circuit as vabove described, byv movement ofcontroller 15 to. .the position Aiv indicated in Fig. 2, motor `65` liscaused to'rotate drawing-fluid from the reservoir 64 by means ofthepumpll anddeliveringit through pipes 6I and 62 to the cylinder'59. torelease the brake band 51. When brakeylinder 59 reaches thejlimit of:its movement byengagement withastop, notshown, pressure tinfthehydraulic system rises until theresisting torque of pump 60 exceeds themaximum torque of which a spring 58 and re-l v motor 65 is capable.,Motorv 6.5; thereupon stalls. but continues to exert its torqueandi-tol maintain pressure in the brakecylinder 59; If; for any reasonleakage should occur anywherev inthe system, motor 65 willresume itsmotion to a sum; cient extent'tc4 replace such leakage while stillmaintaining the desired pressure in the system. Brake band 5'1'- isvthus releasedand-maintained releasedv as long'as thecontroller-"151sclosed, but if for anyvreason a power failure should`occur or the controller 'I5 is opened, motor G5 fwll .cease to exertits pressure' maintainingv torque. and pump 5t will reversehydraulioally,"setting the brake vband 51. In this way danger of-v theappa? ratus running away on a slope canbe positively controlled by theoperator at anytime'and'in case of acrzcidentallA power failure isprecluded automatically-.

For the purpose of shifting dog clutch member 3S to select betweenstraight line travel or steering, a shifter forkl 38 in freev rotationalsliding engagement with a groove in the member 36, is rigidly carriedupon a shifter support rod 89 slidingly mounted in guide sleeves 94 `andfattached to the carbody 3 ,as shown more clearly in Fig. l. As showndiagrammatically in Fig. 2 the ends of rod 89 are joined with hydraulicpistons Sligand 91| arranged to operate in hydraulic cylinders 9,2 and93. The rod Bil-and pistons B Il'and SI operate as a, unit Awhich mayoscillate between the position shown in Fig. 2 'and a position oppositethereto to s hiftthe member 35 from its straight travel position to itssteeringipofsition.

Fluid for the actuation of piston QI is supplied through pipe SB'whichjoins' with outlet port 91 of a'. two way solenoid actuated valve 98.Valve Q8 is provided with an inlet port 9,9which is joined by an inletpipe IGI) with the pipe 6I. Inlike manner fluid for'the actuation ofpiston 50 is supplied through pipe. IBI' vvhich .joins with an outletport I02'of the valvel.. .y

The valve 93 is heldin an'dnormallyoccupies the position shown i'n'Fig 2by 'reason' of the action of spring ID3 which acts upon-valve piston |54as shown. With the valve 98in the position shown in Fig. 2 communicationfrom port 99 to port 91 and thence to cylinder 93 is provided. Also, inthis same position cylinder 92 through port |02 is in communication withexhaust passage |65 which is connected by return flow pipe 195 with thesump 64. With the motor 65 energized and pressure prevailing in the pipeIBI] the dog clutch member 36 is moved to and held in the position shownin Fig. 2. Arranged to act upon the valve piston |04 is a magnet coil I01 which, when energized, shifts the valve 98 so as to admit pressureiluid into cylinder 92 and to permit the exhausting of fluid fromcylinder 93. Leads IOS and |09 are connected with the coil IIl'I so asto join the same with slip rings B9 and I IIJ mounted as previouslydescribed. A brush I I I mounted on the cab I0 engages the slip ringIII) and is connected lby lead I I2 with the controller 15. By movementof the controller 'I5 from its initially closed position designated A toits more remote closed position designated B commutator segment II4 isbrought into play and elec` trical connection Ibetween the coil I01 andpower mains 85 and B is established. When this occurs dog clutch member36 Vis shifted so yas to lock tread 2 against movement and to permit thedrivl ing of tread I either forwardly or in reverse depending upon therotation of motor 55 so as to cause either a right handor a left handturn.

From the foregoing description it will be seen that; the manner'@decorating vthe Vappavatars; may be asiel/1 ws; with the cranestationary the driven in the. direction necessary to cause the.

turn` desiredv At anynstaee .0f-any of; these-maneuvers thef operatormay immediately open lthe.

controlleralS whereupon thebralie band-f5.1 will vbecomeset.,tous.making available a safety funetion addition to th fact that the` motor5,5 re,- mainsin-.comrrnandtot atleast one. of .the two treads atyalltimes.-

Spring 5B1 ispreferably chosen so as to. have suileient Strength 'notonly to positively apply brake band lbut also to resist. motionof.piston 59 .until hydraulic pressure.. substantially exceeds thatrequired to causefhiftigof pistons 9| and 9,2. Whenthis is 'done 'piston53 serves4 the additional functionof an accumulator which stands readyto cause shifting or pistons Si! and 9| irnmediatelv upon Shiftingof'valve' 58 without Wait# ing 4for motor 65 and nunon .tojset underWav.

1.1m a s .elffpropelled revolving Aorarie, yhaving a first andsec'ondsupporting and propelling endless tread, acarbody mounted thereon, a'cabrevolvably mountedfon said carbody, the improvement in propellingandsteeringapparatus therefor comprising a first and 'a-secondindependent tread' driving means for-"said treads .respectively mountedon said carbody, vclutch means kadapted normally to connect vsaid treaddriving means to be driven in unison, means associated with said carbodyand adapted to lock -said first tread driving means and the treadassociated with it when said clutch means is disconnected, a propellershaft drivingly connected to said second tread driving means at alltimes and adapted to be connected to said first tread driving means whensaid clutch means is connected, a reversible electric motor foroperating said propeller shaft mounted on said cab,` transmissiongearing forming a continuously connected driving connection between saidmotor and said propeller shaft, and

less tread, a carbodymounted thereon, a cab revolvably mounted on saidcarbodyfthe improvement in propelling and steering apparatus thereforcomprising a flrst and a second independent tread driving means for saidtreads respectively mounted on said carbody, clutch means adaptednormally to connect said tread driving means to be driven in'unison,operator controlled means to operate the same, selective steering meansadapted to lock said'V first tread driving means when said vclutch meansis disconnected, apropeller shaft drivingly connected to said secondtread driving means at all times and adapted to be connected to saidfirst tread driving means when said clutch means is connected, and are-` less tread, a carbody mounted thereon, a cab revolvably mounted onsaid carbody, the improvement in propelling and steering apparatus etherefor-'comprising independent tread driving means for each of saidtreads mounted on' said carbody, clutch means adapted normally toconnect said tread driving means to be driven"` in unison, meansassociated with said carbody and adapted to lock one of said treaddriving means and the tread associated with it when said clutch means isdisconnected, and a continuously vconnected reversible electric powersource including a shaft drivingly connected to the othery of said treaddriving means at all times.

4. In a control apparatus for a self-propelled vehicle having movabletreads the combination comprising an electrically energized source ofmechanical power, transmission means adapted to form driving connectionsbetween said power source and said treads simultaneously or with one ofthem singly, shifting means adapted to be shifted to cause selection ofsaid driving connections, a normally applied brake adapted to arrestmovement of said transmission means, a, pressure responsive fluidactuated means adapted to release said brake, va pump, an electrictorque motor drivingly connected with said pump, means forming aconnection between the discharge of said pump and said uid actuatedbrake releasing means, a fluid actuated motor adapted to 8. occupyselective positions corresponding to the selective positions of saidshifting means and operatively connected thereto to move the same to andfrom said positions, means forming a hydraulic connection between thedischarge of said pump and said uid actuated motor including fiowdirecting means adapted to cause selectionl of the position to beoccupied by said motor when fluid under pressure is being supplied bysaid pump, and operator controlled means adapted to admit and interrupta supply of energizing current to said torque motor from a commonenergizing current source through which said electrically energizedpower source is also energized and to regulate said flow directing meansto cause selection of said driving connections.

WILL S. BURDICK.

I-I. S. JACOBS.

KARL SCHNEIDER.

REFERENCES CITED The following references are of record in the file ofVthis patent:

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